Whit,
Bought a bunch of Barnes 325 gr. 0.510 dia., XPBs. I am working up loads for my 500 Linebaugh, Reeder African Hunter built on a Ruger Blackhawk Bisley. Starting out with AA#7. QuickLoad gives best velocity, pressure ratios for that powder. I have cast and loaded a NEI 465 gr. KT SWC using WW296 max load, mag primer, Starline brass, velocity approx 1375 fps.. It was a beast!!! Also, same bullet with 2400 to a velocity of approx 1,000 fps., like a 454 C. What loads are you using?
Doc